diff --git a/docs/auto_examples/index.rst b/docs/auto_examples/index.rst
index 4947dd0..b5ee7ab 100644
--- a/docs/auto_examples/index.rst
+++ b/docs/auto_examples/index.rst
@@ -5,7 +5,7 @@ Examples Gallery
 
 Below is the gallery of ``pygmtools`` examples. We build the examples from the introduction of graph matching
 to the variants of graph matching, and finally, we provide examples on the applications of graph matching.
-In each topic, we provide examples on different numerical backends (e.g., pytorch, numpy, paddle, jittor, tensorflow, mindspore).
+In each topic, we provide examples on different numerical backends (e.g., pytorch, numpy, paddle, jittor).
 
 
 
@@ -35,7 +35,7 @@ Introduction of Graph Matching: Matching Isomorphic Graphs
 .. only:: html
 
   .. image:: /auto_examples/1.matching_isomorphic_graphs/images/thumb/sphx_glr_plot_isomorphic_graphs_numpy_thumb.png
-    :alt:
+    :alt: Numpy Backend Example: Matching Isomorphic Graphs
 
   :ref:`sphx_glr_auto_examples_1.matching_isomorphic_graphs_plot_isomorphic_graphs_numpy.py`
 
@@ -52,7 +52,7 @@ Introduction of Graph Matching: Matching Isomorphic Graphs
 .. only:: html
 
   .. image:: /auto_examples/1.matching_isomorphic_graphs/images/thumb/sphx_glr_plot_isomorphic_graphs_pytorch_thumb.png
-    :alt:
+    :alt: PyTorch Backend Example: Matching Isomorphic Graphs
 
   :ref:`sphx_glr_auto_examples_1.matching_isomorphic_graphs_plot_isomorphic_graphs_pytorch.py`
 
@@ -69,7 +69,7 @@ Introduction of Graph Matching: Matching Isomorphic Graphs
 .. only:: html
 
   .. image:: /auto_examples/1.matching_isomorphic_graphs/images/thumb/sphx_glr_plot_isomorphic_graphs_jittor_thumb.png
-    :alt:
+    :alt: Jittor Backend Example: Matching Isomorphic Graphs
 
   :ref:`sphx_glr_auto_examples_1.matching_isomorphic_graphs_plot_isomorphic_graphs_jittor.py`
 
@@ -86,7 +86,7 @@ Introduction of Graph Matching: Matching Isomorphic Graphs
 .. only:: html
 
   .. image:: /auto_examples/1.matching_isomorphic_graphs/images/thumb/sphx_glr_plot_isomorphic_graphs_paddle_thumb.png
-    :alt:
+    :alt: Paddle Backend Example: Matching Isomorphic Graphs
 
   :ref:`sphx_glr_auto_examples_1.matching_isomorphic_graphs_plot_isomorphic_graphs_paddle.py`
 
@@ -126,7 +126,7 @@ Variant of Graph Matching: Seeded Graph Matching
 .. only:: html
 
   .. image:: /auto_examples/2.seeded_graph_matching/images/thumb/sphx_glr_plot_seed_graph_match_numpy_thumb.png
-    :alt:
+    :alt: Numpy Backend Example: Seeded Graph Matching
 
   :ref:`sphx_glr_auto_examples_2.seeded_graph_matching_plot_seed_graph_match_numpy.py`
 
@@ -143,7 +143,7 @@ Variant of Graph Matching: Seeded Graph Matching
 .. only:: html
 
   .. image:: /auto_examples/2.seeded_graph_matching/images/thumb/sphx_glr_plot_seed_graph_match_pytorch_thumb.png
-    :alt:
+    :alt: PyTorch Backend Example: Seeded Graph Matching
 
   :ref:`sphx_glr_auto_examples_2.seeded_graph_matching_plot_seed_graph_match_pytorch.py`
 
@@ -160,7 +160,7 @@ Variant of Graph Matching: Seeded Graph Matching
 .. only:: html
 
   .. image:: /auto_examples/2.seeded_graph_matching/images/thumb/sphx_glr_plot_seed_graph_match_jittor_thumb.png
-    :alt:
+    :alt: Jittor Backend Example: Seeded Graph Matching
 
   :ref:`sphx_glr_auto_examples_2.seeded_graph_matching_plot_seed_graph_match_jittor.py`
 
@@ -177,7 +177,7 @@ Variant of Graph Matching: Seeded Graph Matching
 .. only:: html
 
   .. image:: /auto_examples/2.seeded_graph_matching/images/thumb/sphx_glr_plot_seed_graph_match_paddle_thumb.png
-    :alt:
+    :alt: Paddle Backend Example: Seeded Graph Matching
 
   :ref:`sphx_glr_auto_examples_2.seeded_graph_matching_plot_seed_graph_match_paddle.py`
 
@@ -217,7 +217,7 @@ Variant of Graph Matching: Discovering Subgraphs
 .. only:: html
 
   .. image:: /auto_examples/3.discovering_subgraphs/images/thumb/sphx_glr_plot_subgraphs_numpy_thumb.png
-    :alt:
+    :alt: Numpy Backend Example: Discovering Subgraphs
 
   :ref:`sphx_glr_auto_examples_3.discovering_subgraphs_plot_subgraphs_numpy.py`
 
@@ -234,7 +234,7 @@ Variant of Graph Matching: Discovering Subgraphs
 .. only:: html
 
   .. image:: /auto_examples/3.discovering_subgraphs/images/thumb/sphx_glr_plot_subgraphs_pytorch_thumb.png
-    :alt:
+    :alt: PyTorch Backend Example: Discovering Subgraphs
 
   :ref:`sphx_glr_auto_examples_3.discovering_subgraphs_plot_subgraphs_pytorch.py`
 
@@ -251,7 +251,7 @@ Variant of Graph Matching: Discovering Subgraphs
 .. only:: html
 
   .. image:: /auto_examples/3.discovering_subgraphs/images/thumb/sphx_glr_plot_subgraphs_jittor_thumb.png
-    :alt:
+    :alt: Jittor Backend Example: Discovering Subgraphs
 
   :ref:`sphx_glr_auto_examples_3.discovering_subgraphs_plot_subgraphs_jittor.py`
 
@@ -268,7 +268,7 @@ Variant of Graph Matching: Discovering Subgraphs
 .. only:: html
 
   .. image:: /auto_examples/3.discovering_subgraphs/images/thumb/sphx_glr_plot_subgraphs_paddle_thumb.png
-    :alt:
+    :alt: Paddle Backend Example: Discovering Subgraphs
 
   :ref:`sphx_glr_auto_examples_3.discovering_subgraphs_plot_subgraphs_paddle.py`
 
@@ -308,7 +308,7 @@ Variant of Graph Matching: Multi-Graph Matching
 .. only:: html
 
   .. image:: /auto_examples/4.multi-graph_matching/images/thumb/sphx_glr_plot_multi_graph_match_jittor_thumb.png
-    :alt:
+    :alt: Jittor Backend Example: Multi-Graph Matching
 
   :ref:`sphx_glr_auto_examples_4.multi-graph_matching_plot_multi_graph_match_jittor.py`
 
@@ -325,7 +325,7 @@ Variant of Graph Matching: Multi-Graph Matching
 .. only:: html
 
   .. image:: /auto_examples/4.multi-graph_matching/images/thumb/sphx_glr_plot_multi_graph_match_numpy_thumb.png
-    :alt:
+    :alt: Numpy Backend Example: Multi-Graph Matching
 
   :ref:`sphx_glr_auto_examples_4.multi-graph_matching_plot_multi_graph_match_numpy.py`
 
@@ -342,7 +342,7 @@ Variant of Graph Matching: Multi-Graph Matching
 .. only:: html
 
   .. image:: /auto_examples/4.multi-graph_matching/images/thumb/sphx_glr_plot_multi_graph_match_pytorch_thumb.png
-    :alt:
+    :alt: PyTorch Backend Example: Multi-Graph Matching
 
   :ref:`sphx_glr_auto_examples_4.multi-graph_matching_plot_multi_graph_match_pytorch.py`
 
@@ -359,7 +359,7 @@ Variant of Graph Matching: Multi-Graph Matching
 .. only:: html
 
   .. image:: /auto_examples/4.multi-graph_matching/images/thumb/sphx_glr_plot_multi_graph_match_paddle_thumb.png
-    :alt:
+    :alt: Paddle Backend Example: Multi-Graph Matching
 
   :ref:`sphx_glr_auto_examples_4.multi-graph_matching_plot_multi_graph_match_paddle.py`
 
@@ -399,7 +399,7 @@ Application of Graph Matching: Model Fusion by Graph Matching
 .. only:: html
 
   .. image:: /auto_examples/5.model_fusion/images/thumb/sphx_glr_plot_model_fusion_pytorch_thumb.png
-    :alt:
+    :alt: PyTorch Backend Example: Model Fusion by Graph Matching
 
   :ref:`sphx_glr_auto_examples_5.model_fusion_plot_model_fusion_pytorch.py`
 
@@ -416,7 +416,7 @@ Application of Graph Matching: Model Fusion by Graph Matching
 .. only:: html
 
   .. image:: /auto_examples/5.model_fusion/images/thumb/sphx_glr_plot_model_fusion_jittor_thumb.png
-    :alt:
+    :alt: Jittor Backend Example: Model Fusion by Graph Matching
 
   :ref:`sphx_glr_auto_examples_5.model_fusion_plot_model_fusion_jittor.py`
 
@@ -433,7 +433,7 @@ Application of Graph Matching: Model Fusion by Graph Matching
 .. only:: html
 
   .. image:: /auto_examples/5.model_fusion/images/thumb/sphx_glr_plot_model_fusion_paddle_thumb.png
-    :alt:
+    :alt: Paddle Backend Example: Model Fusion by Graph Matching
 
   :ref:`sphx_glr_auto_examples_5.model_fusion_plot_model_fusion_paddle.py`
 
@@ -472,7 +472,7 @@ Application of Graph Matching: Matching Image Keypoints by QAP Solver
 .. only:: html
 
   .. image:: /auto_examples/6.image_matching_by_QAP/images/thumb/sphx_glr_plot_image_matching_numpy_thumb.png
-    :alt:
+    :alt: Numpy Backend Example: Matching Image Keypoints by QAP Solvers
 
   :ref:`sphx_glr_auto_examples_6.image_matching_by_QAP_plot_image_matching_numpy.py`
 
@@ -489,7 +489,7 @@ Application of Graph Matching: Matching Image Keypoints by QAP Solver
 .. only:: html
 
   .. image:: /auto_examples/6.image_matching_by_QAP/images/thumb/sphx_glr_plot_image_matching_pytorch_thumb.png
-    :alt:
+    :alt: PyTorch Backend Example: Matching Image Keypoints by QAP Solvers
 
   :ref:`sphx_glr_auto_examples_6.image_matching_by_QAP_plot_image_matching_pytorch.py`
 
@@ -506,7 +506,7 @@ Application of Graph Matching: Matching Image Keypoints by QAP Solver
 .. only:: html
 
   .. image:: /auto_examples/6.image_matching_by_QAP/images/thumb/sphx_glr_plot_image_matching_paddle_thumb.png
-    :alt:
+    :alt: Paddle Backend Example: Matching Image Keypoints by QAP Solvers
 
   :ref:`sphx_glr_auto_examples_6.image_matching_by_QAP_plot_image_matching_paddle.py`
 
@@ -523,7 +523,7 @@ Application of Graph Matching: Matching Image Keypoints by QAP Solver
 .. only:: html
 
   .. image:: /auto_examples/6.image_matching_by_QAP/images/thumb/sphx_glr_plot_image_matching_jittor_thumb.png
-    :alt:
+    :alt: Jittor Backend Example: Matching Image Keypoints by QAP Solvers
 
   :ref:`sphx_glr_auto_examples_6.image_matching_by_QAP_plot_image_matching_jittor.py`
 
@@ -563,7 +563,7 @@ Application of Graph Matching: Matching Image Keypoints by Graph Matching Neural
 .. only:: html
 
   .. image:: /auto_examples/7.image_matching_by_NN/images/thumb/sphx_glr_plot_deep_image_matching_pytorch_thumb.png
-    :alt:
+    :alt: PyTorch Backend Example: Matching Image Keypoints by Graph Matching Neural Networks
 
   :ref:`sphx_glr_auto_examples_7.image_matching_by_NN_plot_deep_image_matching_pytorch.py`
 
@@ -580,7 +580,7 @@ Application of Graph Matching: Matching Image Keypoints by Graph Matching Neural
 .. only:: html
 
   .. image:: /auto_examples/7.image_matching_by_NN/images/thumb/sphx_glr_plot_deep_image_matching_jittor_thumb.png
-    :alt:
+    :alt: Jittor Backend Example: Matching Image Keypoints by Graph Matching Neural Networks
 
   :ref:`sphx_glr_auto_examples_7.image_matching_by_NN_plot_deep_image_matching_jittor.py`
 
@@ -597,7 +597,7 @@ Application of Graph Matching: Matching Image Keypoints by Graph Matching Neural
 .. only:: html
 
   .. image:: /auto_examples/7.image_matching_by_NN/images/thumb/sphx_glr_plot_deep_image_matching_paddle_thumb.png
-    :alt:
+    :alt: Paddle Backend Example: Matching Image Keypoints by Graph Matching Neural Networks
 
   :ref:`sphx_glr_auto_examples_7.image_matching_by_NN_plot_deep_image_matching_paddle.py`